Iridium solar array flares

From: Matson, Robert (ROBERT.D.MATSON@saic.com)
Date: Thu Dec 20 2001 - 16:26:32 EST

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    Hi All,
    
    Ron Lee and Ed Light have correctly diagnosed Anthony's IRIDFLAR
    double-flare prediction phenomenon:  as they say in software circles,
    "it's not a bug, it's a feature!"  ;-)  Solar array flares from Iridium
    satellites
    are slightly more rare than regular flares because most of the time the
    solar arrays are pointed at the sun.  But there are times for each plane of
    satellites when the solar beta angle (the angle between the satellite
    orbital plane and the sun vector) is too high for the two-axis gimbal
    to track the sun.  In the more extreme cases, the angle between the
    solar array normal and the sun is high enough that the specular
    reflection intersects the earth, and a solar array flare is possible.
    
    The vast majority of solar array flares occur within a couple months
    of the summer solstice (April-August in northern hemisphere, October-
    February in the southern hemisphere).
    
    Cheers,
    Rob
    
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